Bulbs or similar vessels and method for manufacturing same



R. LANGLOYS 3,154,230

BULBS OR SIMILAR VESSELS AND METHOD FOR MANUFACTURING SAME Oct. 27, 1964 Filed Sept. 11, 1962 WI?! 6y;

United States Patent 3,154,230 BULBS 0R SIMILAR VESSELS AND METHGD FOR MANUFACTURING SAME Rmi Langioys, Saint-Cloud, France, assignor to Ren Anrep, Suresnes, Seine, France Filed Sept. 11, 1962, Ser. No. 222,823 Claims priority, application France Sept. 12, 1961 4 Claims. (Cl. 225-2) The present invention relates generally to pharmaceutic bulbs or other similar glass vessels, and more particularly to such glass bulbs adapted to be cut open without applying a file or other cutting tools.

In order to cut open a pharmaceutic bulb or glass vessel, use is generally made of a hardened-steel file adapted to produce a preliminary, incipient breaking groove or streak on a necked-down portion of the bulb, so that the latter may readily be broken open by hand when necessary. This method results however in a risk of the bulb being broken irregularly and the user being accidentally hurt.

Various other methods have therefore been proposed in view of eliminating the use of the file and of providing bulbs adapted to be opened manually, by simply twisting or bending the tip thereof.

One such method comprises inducing in the bulb a partial, circularly directed, tension effort, by means of an annealed-enamel ring.

This method requires however a lughly accurate enamel composition and a very critical annealing temperature. On the other hand, the tensions normally induced in the glass-either during the manufacturing process, or arbi trarily-are not readily controllable and very unstable, owing to temperature variations and ageing. Moreover, at the instant of the bulb being broken open, the enamel bursts into pieces of more or less larger sizes, which may be drawn, by suction, into the more or less evacuated bulb.

According to another known process, the bulb is subjected to a frosting or grinding operation at the area adapted to be broken, by projecting abrasive particles on the glass while in a hot condition. The complex mechanical arrangement required for carrying this method into effect (projection of the abrasive particles by air pressure etc.) will however provide results of a rather variable nature, on account of the unstable operating conditions due to the irregular softening temperature of the glass, the density of the projecting particles, the penetrating depth of the particles, etc.

Yet another known method resorts to a cleavage or splitting operation by means of a hardened-steel disc, the twisting direction being indicated on the glass bulb. This cleavage must however be proportional to the glass thickness, a requirement not readily achieved in practice, since the glass utilized may vary in thickness by several hundredth of millimeters during the manufacture of the bulb, resulting, for the same cleavage operation, either in an untimely breakage of the glass, or in the latter being impossible to be broken open.

Still another method has been proposed-although with little practical success-producing an incipient cutting groove on a tapered portion of the glass bulb by means of discs made either of hardened steel or of abrasive par ticles, such as bonded carborundum and bonded diamond powder, or by discs of soft steel rotating at a high speed and afiecting thermally the glass.

All the methods as mentioned hereinabove for cutting open the neck of a bulb, are used in conjunction with bulb manufacturing machines, but are unable to provide the preliminary cutting streak required, the accuracy of which-both as concerns the tension eifect and the cleavageis diflicult to be controlled.

As described, the known methods listed above consistice ing essentially in notching, cleaving or scratching the bulb glass, provide very unstable results, since, on one hand, these results are achieved by means of materials which are harder than the glass and thus induce therein, through heating, uncontrollable tension efforts and, on the other hand, the notches, cleavages or cracks provided are either inadequate to enable the cutting to be effected manually, or are too marked and may then cause the extension of such notches and consequently bring about untimely breakages during the handling of the bulbs, or even through ageing of the latter.

The underlying principle of the present invention relates to the use of products, adapted to create incipient cutting grooves, of a hardness lower than that of the glass, and tending rather to produce a kind of frosting or grinding effect of the bulb glass, while heating the latter as little as possible, so as to avoid inducing tension efiects therein.

Among all the materials softer than glass, such as copper, zinc, brass, aluminum, plastic substances, rubber, which provide a more or less marked frosting, and as shown by systematic testing experiments carried out by the applicant, the aluminum and its alloys, such as duralumin, furnished the most satisfactory results for this operation.

Under certain operating conditions, it has been found that the friction on the glass of the aluminum or an alloy thereof-such as duralumincaused the occurrence of a kind of aifinity of these materials with respect to one another.

It is believed that on account of its low melting point, an aluminum or duralumin disc, for instance, rotating at a predetermined speed in contact relationship with the glass, will produce a kind of interchange between the two substances, occurring schematically as follows:

The frosting or grinding of the glass will produce a separation of glass particles from the bulb surface which become encrusted on the aluminum or aluminum alloy disc, causing these glass grains to be inserted along the edge of the disc. These glass particles, inserted into the metal, have sharp breakage angles.

It is however probable that this occurrence is far more complex than this rather simplified explanation; in effect, the diagrams derived from an analysis based on the electronic diffraction enable to reveal, on the periphery of the disc, during and after the use, glass and aluminum components, such as, for instance, an aluminum silicate (A1 0 4SiO H O).

This interchange between the glass and the aluminum also occurs in the other direction, i.e. according to the rotating speed of the disc, there is formed on the glass a more or less visible dark-brown or black deposit derived from the aluminum or aluminum alloy disc used.

The particularly satisfactory results achieved according to the present invention are due, no doubt, to the action of this aluminum or aluminum alloy-or of their components-on the glass.

The sharp-edged glass particles embedded on the disc edge cause a limited grinding effect, probably due to the fact that said abrasion is achieved by means of a material the hardness of which is, at most, equal to that of the glass. Besides, this abrasion eifect is easily controllable by means of the peripheral speed of the disc and the pressure thereof on the bulb. It is thus possible to obtain excellent incipient cutting grooves on the bulbs or other similar vessels, which are not too easily broken open, nor to difficult to cut.

The various testing experiments leading to the practical development of the present invention have disclosed a remarkable property of the aluminum or aluminum alloy disc, for instance a duralumin disc, whereby a constant renewal of the glass or glass-aluminum components is 3. taking place on the edge of the disc, in proportion with the elimination of said particles by the abrasion opera tion.

It is also to be noted that said abrasion does not just result in a more or less frosting or grinding effect of the glass-which would not be sufiiciently strong to assure a constant and uniform break-but also a surface consisting of a plurality of sharp-edged polyhedral angles due, as it were, by the glass surface being torn off by the numerous tools formed by the particles of glass or glass components inserted on the periphery of the aluminum or aluminum alloy disc.

Each one of these angles forms a preferred breakage point, without however causing any void, nor notch or cleavage on the glass surface.

The presence of these numerous sharp-edged angles on the abraded glass surface is emphasized by the fact that the resulting bulb, when annealed at a temperature close to the softening point of the glassi.e. about 600 C. thus causing the angles to be rounded off, recovers its entire ruggedness, although the frosting remains visible to the eye.

This property may, besides, be used to reduce, by annealing at a controlled temperature, the brittleness of the incipient cutting notch.

The present invention has for its object a method of manufacturing bulbs or other similar vessels adapted to be cut open without applying a file, comprising providing on said bulb, on the area Where it is desired to cause it to be cut open, a special abrasion operation by means of a tool such as a disc, a wire, ribbon, made of materials such as aluminum or aluminum alloys-such as duralumin-thus achieving a self-abrasion action.

This method enables to impart to the selected area a controlled brittleness, enabling the bulb to resist the various handling operations, while allowing the user to manually break the bulb open, without applying the file, and under the safest conditions.

According to the glass qualities, discs or other tools, of various thicknesses, are used, the relative linear speed of which depends also on the operating temperature, the thickness of the glass, etc. Satisfactory results have been obtained at relative linear speeds in the range of 1 to 8 meters per second. For each type of glass, the upper and lower speed limits may be experimentally determined, the results obtained outside these limits being either negative, or insufficient.

Preferably, the incipient breaking groove is produced on the neck of the bulb, at the area around a constricted portion of said neck.

The incipient breaking groove covers, at least, a portion of the bulb periphery.

Another advantage of the method according to the invention lies in that metal particles deposit generally on I 2 of which has a constricted portion 3 at its base, the bulb being maintained in position, by means of chuck jaws 4, on a support or holder 5 adapted to be slowly rotated, through a pulley 6 carrying a belt 7, about an axis 8 coinciding with the axis of the bulb.

The axis 8 of the support rests on a frame 9 which also carries an electric motor 10 driving a pulley 11.

On shaft 12 of the motor is pivoted an arm 13 urged towards the support 5 by a spring 14 secured, in turn, to

a lug 15 fixed on the frame. The arm 13 carries a shaft 16 on which is secured, on one hand, a pulley 17 conconstricted portion 3 of the bulb neck, said disc will form on the latter a peripheral groove 20, along which the bulb may, when necessary, be broken open.

What I claim is:

1. In a method of manufacturing bulbs or the like glass vessels formed with a portion of reduced strength along which said vessels may be readily broken open by hand, the step comprising wearing of said vessel at the said portion by means of a tool made of a material the hardness of which is less than that of the glass out of which said vessel is made.

2. The method of claim 1 wherein said material is selected from the group containing aluminum and aluminum alloys.

3. The method of claim 2 wherein said tool is a disc adapted to be rotated in contact relationship with said portion of said vessel.

4. The method of claim 3 wherein said disc is rotated at a speed such that a deposit of aluminum compound appears on said portion of said vessel.

References Cited in the file of this patent UNITED STATES PATENTS 1,663,093 Peiler Mar. 20, 1928 2,116,129 Stinger May 3, 1938 2,486,321 OSullivan Oct. 25, 1949 2,517,604 Smith Aug. 8, 1950 2,947,117 Greene et a1. Aug. 2, 1960 FOREIGN PATENTS 167,900 Australia June 28, 1956 

1. IN A METHOD OF MANUFACTURING BULBS OR THE LIKE GLASS VESSELS FORMED WITH A PORTION OF REDUCED STRENGTH ALONG WHICH SAID VESSELS MAY BE READILY BROKEN OPEN BY HAND, THE STEP COMPRISING WEARING OF SAID VESSEL AT THE SAID PORTION BY MEANS OF A TOOL MADE OF A MATERIAL THE HARD- 